I think the answer is b as in boy.
A is true because they do have a true nucleus or membrane-bound organelles .
Your answer is gravitational forces
The correct term to fill in the blank would be pancreas. It is the pancreas that is the primary site for non essential amino acid production in humans. It can be found in the abdomen. There are two functions that the pancreas do. First, it aids in the digestion, an exocrine function. Second, it helps in the regulation of substances inside the body, an endocrine function.